岩溶洞穴微生物沉积碳酸钙——以贵州石将军洞为例

为探讨洞穴微生物沉积碳酸钙作用对洞穴沉积物的影响,利用传统生物学方法,采集贵州中西部地区石将军洞洞穴沉积物表面的微生物样品,结合洞穴监测数据和理化背景资料,利用B-4培养基和B-4C培养基对洞穴细菌进行筛选和纯化,分离出能沉积碳酸钙的菌种,观察和了解洞穴细菌形成的CaCO3晶体,应用X射线衍射分析仪(XRD)分析细菌形成的CaCO3晶体成分,并利用扫描电子显微镜(SEM)观察晶体结构特征。结果表明:1)在B-4培养基下微生物产生的碳酸钙晶体主要为方解石、球霰石和方解石混合物、球霰石,这种变化与培养基pH值的增幅相关;同时,在添加Mg离子的B-4C培养基下形成的碳酸钙晶体主要为方解石,此外,研究中并未检测到文石晶体。2)通过SEM扫描,发现微生物作用形成的碳酸钙晶体存在不规则六方体、柱状体、四方体层状、半球状等,这些晶体形态在化学作用系统下少见,多见于微生物作用形成的方解石。此外,晶体中微生物作用痕迹明显,微生物作用贯穿于整个沉积过程。     

桂林罗汉肚洞细菌群落的环境驱动机制及群落构建过程

[目的] 洞穴被认为是黑暗、寡营养的极端环境,是研究深地生物圈的天然实验室。洞穴内部小生境丰富,不同洞穴水文条件和环境因子等差异大,尽管微生物群落在不同的洞穴中均显示出较强的生境特异性,但对不同相态（固相和液相）环境样本中微生物群落的环境驱动机制以及群落构建的生态学过程的认识却十分薄弱。为了回答上述科学问题。[方法] 本文选择了桂林地区典型的喀斯特洞穴罗汉肚洞,针对洞穴中不同生境（岩壁、沉积物、水潭积水、滴水和地下河河水）进行系统采样以及16S rRNA扩增子的高通量测序分析和理化参数的测试。[结果] 结果表明洞穴中不同生境微生物群落结构具有显著的生境特异性。岩壁样品以放线菌门（Actinobacteria）为优势类群,沉积物中的优势类群则为酸杆菌门（Acidobacteria）,所有水样微生物群落均以g-变形菌纲（Gammaproteobacteria）为主。温度、风化指数以及SO₄^2-浓度显著影响罗汉肚岩壁和沉积物等固相样本中微生物的群落结构,其中USCg和假单胞菌属（Pseudomonas）与温度呈正相关,假诺卡氏菌属（Pseudonocardia）、土壤红色杆形菌（Solirubrobacter）和芽单胞菌属（Gemmatimonas）则与温度显著负相关。而滴水、水潭积水以及地下河河水等液相样本中微生物群落则与电导率（EC）和溶解氧（DO）的含量显著相关。细菌群落的共生网络具有明显的模块性,不同微生物类群间以正相关的合作关系为主,以共同抵抗洞穴中的极端条件。固相样本中群落构建确定性过程（48.75%）与随机性过程（51.25%）的贡献基本相等,但液相样本中微生物的群落构建则以随机过程占主导（64.76%）。[结论] 本研究结果首次揭示了洞穴微生物在不同相态样品中微生物群落的分布规律以及环境驱动机制、网络互作方式以及群落构建等生态学过程的差异,为深刻认识洞穴这一深地生物圈的微生物空间分布特征及微生物与环境之间以及不同微生物类群之间的相互作用提供了新的视角。     

中国洞穴甲壳动物多样性及其对洞穴环境的适应性

简要阐述了洞穴环境的研究现状以及洞穴动物的生态特征,初步探讨了中国洞穴甲壳动物的形成过程、多样性、地理分布以及对洞穴环境的适应性。截止到2008年10月,我国已记录的洞穴甲壳动物(主要指十足目虾类和端足目钩虾类)共有33种,分别隶属6科10属,主要分布在贵州省、广西省等喀斯特洞穴密集地区。洞穴甲壳动物由于长期生活在洞穴的黑暗带,食物匮乏,水温恒定,CO2浓度过高,且O2浓度相对较少的环境中,其在形态结构、消化系统、生理及行为等方面逐渐表现出与地表甲壳动物不同的适应性特征。如:眼缺失、体无色、触角和附肢显著增长、新陈代谢减慢、代谢率小,昼夜节律降低,不能调节体温,生活步调放慢,寿命长,发育周期长等。     

船帆洞旧石器遗址洞穴形成过程与地层划分

本文根据最近发掘所获资料,对万寿岩山船帆洞旧石器时代晚期遗址洞穴的形成过程、洞内地层划分以及与洞外沉积物关系等问题进行初步探讨。提出:船帆洞洞穴的发育明显与区域性断裂及岩体的剪切节理有关;洞内经历数次堆积和冲刷;依岩性、地层关系和哺乳动物化石组合,洞内堆积物可分为Ⅰ(中更新世晚期)、Ⅱ(晚更新世早期)、Ⅲ(晚更新世晚期)和Ⅳ(全新世)4个地层单元。     

湖北和尚洞固氮微生物群落的生境特异性及网络分析

岩溶洞穴是喀斯特地貌的重要组成部分,由于其长期黑暗、寡营养等极端条件,使其成为研究陆地深部生物圈的天然实验室。尽管近年来对洞穴微生物多样性的研究不断深入,但对洞穴中固氮微生物的认识却相对薄弱。【目的】查明洞穴中固氮微生物群落的特征以及与生物、非生物因子之间的关系。【方法】本文以湖北和尚洞为例,通过对固氮菌功能基因nifH进行高通量测序和多元统计分析,系统研究了洞穴内外3种生境(洞穴上覆土壤、洞内松散沉积物以及风化岩壁)固氮微生物群落的空间分布特征及其与环境因子之间的关系。【结果】结果表明和尚洞不同生境间固氮菌群落α多样性存在显著差异(P<0.05),以洞穴上覆土壤α多样性最高,洞穴内沉积物α多样性最低。K+、NO2-和NO3-是驱动和尚洞固氮微生物群落组成的重要因子。和尚洞内固氮菌群落组成和分布具有生境特异性,除慢生根瘤菌属(Bradyrhizobium)在3种生境中相对丰度均较高外,上覆土壤以地杆菌属(Geobacter)占主导,洞穴沉积物以固氮菌属(Azotobacter)占主导,而风化岩壁中地杆菌属(Geobacter)、固氮菌属(Azotobacter)以及需盐红螺菌属(...     

喀斯特洞穴小型土壤节肢动物多样性

研究洞穴土壤节肢动物,有助于了解土壤节肢动物对特殊环境的响应,对于深入认识喀斯特生态过程具有重要意义。以喀斯特洞穴生态系统小型土壤节肢动物为研究对象,采用主成分分析、重复测量方差分析、相关性分析和冗余分析等方法探讨了小型土壤节肢动物与环境因子的相互作用关系。调查共获得小型土壤节肢动物2399个,隶属7纲15目121科。其中,自然林优势类群为等节跳科(Isotomidae),洞穴优势类群为奥甲螨科(Oppiidae)。PCA分析显示,洞穴与自然林小型土壤节肢动物群落组成差异明显。洞穴小型土壤节肢动物类群数、密度和Shannon-Wiener指数(H′)显著低于自然林(P<0.05),自然林小型土壤节肢动物类群数、密度和Shannon-Wiener指数(H′)季节差异显著(P<0.05),洞穴类群数、密度和Shannon-Wiener指数(H′)季节差异不明显。相关性分析结果表明,小型土壤节肢动物类群数和Shannon-Wiener指数(H′)与pH值、全磷和光照强度显著相关(P<0.05),密度与pH值、全磷、有机质和光照强度显著相关(P<0.05)。RDA分析表...     

长江口芦苇和互花米草盐沼湿地蟹类洞穴分布特征及主要影响因子

蟹类洞穴是蟹类在潮间带盐沼生存、繁衍的特征性结构,具有重要的生态功能。洞穴分布特征及其影响因子的分析,是深入探讨蟹类及其洞穴的生态系统功能的重要基础。2015年10月,在崇明北滩单一芦苇(Phragmites australis)群落,单一互花米草(Spartina alterniflora)群落和芦苇-互花米草混合群落3种典型生境中,对蟹类洞穴的分布特征及其相关的大型底栖动物、植被、沉积物等的特征参数进行了调研与分析。结果表明,生境类型差异对蟹类洞穴分布特征及相关生境因子具有重要影响。蟹类洞穴的分布密度和开口直径在不同生境间存在显著差异(P0.05),且单一芦苇群落生境内洞穴密度要显著高于单一互花米草群落生境(P0.05),洞穴开口直径在单一互花米草生境要显著高于单一芦苇生境(P0.05);大型底栖动物生物量、密度、植物地下部分生物量在不同生境间差异不显著(P0.05),而植株密度、活植株高度、植物地上部分生物量以及沉积物含水率、p H、氧化还原电位在不同生境间存在显著差异(P0.05)。沉积物中值粒径,总氮含量和总碳含量在不同生境间的差异随深度不同会发生变化。不同生境主要生境因子的差异是导致蟹类洞穴分布特征不同的根本原因;蟹类洞穴分布特征受多个生境因子的综合作用。筛选的生境因子的组合虽然与洞穴分布特征具有显著相关性,但相关系数较小。未来研究中需要拓展生境因子涵盖范围,加强多因子综合作用分析。     

洞穴鱼类眼部退化机制的研究进展

黑暗环境中的洞穴鱼类眼部结构发生了退化,但不同洞穴鱼物种眼部退化程度存在差异,从眼部结构的部分缺失到完全消失的情况均存在。目前研究表明,不论是达尔文的自然选择学说,还是木村资生的中性进化理论均不能很好地解释洞穴鱼类眼部退化的产生机制。洞穴鱼类眼部退化是一个复杂的过程,若要揭示其机制需汇集多个学科的研究优势。该文介绍了国内外洞穴鱼类眼部退化研究领域的形态解剖学、发育生物学、动物行为学及分子遗传学研究进展,并对洞穴鱼眼部退化的研究现状与发展提出了一些思考和建议。     

野生大鲵繁殖洞穴生态环境的初步研究

为了探明野生大鲵(Andrias davidianus)自然繁殖所需要的主要生态条件,给人工养殖条件下大鲵的自然繁殖提供生态学依据,对张家界国家级大鲵保护区境内野生大鲵的栖息繁殖洞穴进行生态学考察。对海拔、洞口的宽度与高度等10个生态因子进行定量观测和主成分分析,结果表明,影响大鲵选择繁殖洞穴的主要因子是海拔、洞口高度、洞底组成,以及洞穴中水的透明度、pH、流速、饵料丰度7个因子。对大鲵繁殖洞穴相连河段进行调查,发现多为山溪流。对繁殖洞穴中水的溶解氧、化学耗氧量、硫化物等5项主要指标进行检测,除硫化物外,其他指标多达到国家饮用水的水质标准,可见大鲵自然繁殖对洞穴与水质的要求较高。     

英格兰洞穴苔藓植物区系特征及其岩溶沉积研究

根据作者1998－2000年采自英格兰7个岩溶洞穴452份苔藓植物标本研究,英格兰岩溶洞穴苔藓植物区系具有下列特征：（1）区系种类由20科41属65种（含变种亚种）组成;（2）区系地理成分含北温带分布（52．30％）、温带欧洲分布（15．38％）、欧洲－亚洲分布（1．54％）、欧洲－北美分布（12．31％）、旧世界温带分布（4．62％）、英国特有（1．54％）和世界广泛分布（12．31％）等7种成分;（3）生活型含高丛集型（9．22％）、矮丛集型（20％）、交织型（61．54％）、扇型（4．08％）和平铺型（4．08％）5种类型。14种洞穴苔藓植物参与了洞穴洞口钙华沉积,沉积形态包括钟乳石、洞壁钙华、洞底泉华和洞底滴水钙华4种类型。     

塑料大棚渗灌灌水下限对番茄生长和产量的影响

利用土壤水分张力计监测土壤水分吸力的变化,以灌水时30cm土层的土壤水分吸力表示渗灌灌水下限,研究灌水下限为10、16、25、40和63kPa时对塑料大棚番茄生长和产量的影响．结果表明,番茄株高、生物量分别随灌水下限的增大而减小．番茄的产量和水分利用率与灌水下限间的关系曲线为抛物线,而茎粗／株高比与灌水下限间的关系曲线为三次多项式曲线．灌水下限不同,番茄的根／冠比(R／S)动态不同,番茄根系与株冠的生长状况不同．灌水下限在25～33kPa时,番茄植株生长健壮,根冠比例协调,产量大,水分利用率高．此指标作为渗灌灌水下限,灌水时土壤水分的含量比常规灌水低,灌水次数少,有利于提高保护地番茄栽培的水分利用率和劳动生产率．     

Opportunities for woody crop production using treated wastewater in Egypt. II. Irrigation strategies

An Egyptian national program targets annual reuse of 2.4 billion m3 of treated wastewater (TWW) to irrigate 84,000 ha of manmade forests in areas close to treatment plants and in the desert. To evaluate the feasibility of such afforestation efforts, we describe information about TWW irrigation strategies based on (1) water use of different tree species, (2) weather conditions in different climate zones of Egypt, (3) soil types and available irrigation systems, and (4) the requirement to avoid deep percolation losses that could lead to groundwater contamination. We conclude that drip irrigation systems are preferred, that they should in most cases use multiple emitters per tree in order to increase wetted area and decrease depth of water penetration, that deep rooting should be encouraged, and that in most situations irrigation system automation is desirable to achieve several small irrigations per day in order to avoid deep percolation losses. We describe directed research necessary to fill knowledge gaps about depth of rooting of different species in sandy Egyptian soils and environments, tree crop coefficients needed for rational irrigation scheduling, and depth of water penetration under different irrigation system designs. A companion paper addresses recommendations for afforestation strategies (see Zalesny et al. 2011, this issue).     

Significance of summer fog and overcast for drought stress and ecological functioning of coastal California endemic plant species

Aim Fog drip is a crucial water source for plants in many ecosystems, including a number of global biodiversity hotspots. In California, dozens of rare, drought‐sensitive plant species are endemic to coastal areas where the dominant summer moisture source is fog. Low clouds that provide water to these semi‐arid ecosystems through fog drip can also sharply reduce evaporative water losses by providing shade. We quantified the relative hydrological importance of cloud shading vs. fog drip. We then examined how both factors influence the range dynamics of an apparently fog‐dependent plant species spanning a small‐scale cloud gradient. Location The study area is on Santa Cruz Island off the coast of southern California. It is near the southern range limit of bishop pine (Pinus muricata D. Don), a tree endemic to the coasts of California and Baja, Mexico. Methods We measured climate across a pine stand along a 7 km, coastal–inland elevation transect. Short‐term (1–5 years) monitoring and remote sensing data revealed strong climatic gradients driven primarily by cloud cover. Long‐term (102 years) effects of these gradients were estimated using a water balance model. Results We found that shade from persistent low clouds near the coast reduced annual drought stress by 22–40% compared with clearer conditions further inland. Fog drip at higher elevations provided sufficient extra water to reduce annual drought stress by 20–36%. Sites located at both high elevation and nearer the coast were subject to both effects. Together, these effects reduced average annual drought stress by 56% and dramatically reduced the frequency of severe drought over the last century. At lower elevation (without appreciable fog drip) and also near the inland edge of the stand (with less cloud shading) severe droughts episodically kill most pine recruits, thereby limiting the local range of this species. Main conclusions Persistent cloud shading can influence hydrology as much as fog drip in cloud‐affected ecosystems. Understanding the patterns of both cloud shading and fog drip and their respective impacts on ecosystem water budgets is necessary to fully understand past species range shifts and to anticipate future climate change‐induced range shifts in fog‐dependent ecosystems.     

Yield and quality of forage maize (<i>Zea mays</i> L.) with different levels of subsurface drip irrigation and plant density

The scarcity of water in arid and semiarid regions of the world is a problem that every day increases by climate change. The subsurface drip irrigation (SDI) and changes in population density of plants are alternatives that can be used to make a sustainable use of water. Therefore, the objectives of this study were to determine the combination that allows for an increased corn performance and efficient use of water without losing the quality of forage. Three different irrigation levels were applied through a system of a SDI at three different densities of forage maize plants in an arid region. The results demonstrated that by applying different levels of water, either enough or lack of soil moisture is created, which is directly reflected in crop yield, and its determining variables such as green forage and dry matter yield, and nutritional quality. The irrigation level to a 100% of potential evapotranspiration (PET), at a density of 80000 plants/ha, increased yield of green forage to 57664 kg/ha; crude protein was 8.59%, while the rest of the quality parameters decreased. This study allowed to conclude that the irrigation level was the major factor in the response of the crop.     

The cave bear’s hibernation: reconstructing the physiology and behaviour of an extinct animal

Abstract

When studying an extinct species such as the cave bear (Ursus spelaeus ROSENMÜLLER 1794), it is possible to apply a variety of molecular biology techniques such as the study of stable isotopes or mitochondrial DNA (mDNA) to infer patterns of behaviour or physiology that would otherwise remain concealed. Throughout Europe and along time, differences in the isotopic values (δ¹³C and δ¹⁵N) of cave bears arise from environmental differences and the Pleistocene climatic evolution. The climate determines the hibernation length, during which the cave bears undergo a particular physiology that can be related to an increase in δ¹⁵N during climate cooling. In order to verify whether hibernation affected the isotopic values, we compared cave bears in different ontogenetic stages. The results show that perinatal values reflect the values for mothers during hibernation, while juveniles show differences in maternal investment. A previous study in the literature based on complete mitochondrial DNA sequences of several individuals collected from closely situated caves showed that each cave housed, almost exclusively, a single lineage of haplotypes. This pattern suggests extreme fidelity to the birth site, or homing behaviour, and that cave bears formed stable maternal social groups, at least for the purpose of hibernation. Studies of this type offer unexpected data on the palaeobiology of this extinct animal.     

Chromium Adsorption by Three Yeast Strains Isolated from Sediments in Morocco

Kartchner Caverns is an oligotrophic subterranean environment that hosts a wide diversity of actively growing calcite speleothems (secondary mineral deposits). In a previous study, we demonstrated that bacterial communities extracted from these surfaces are quite complex and vary between formations. In the current study, we evaluated the influence of several environmental variables on the superficial bacterial community structure of 10 active formations located in close proximity to one another in a small room of Kartchner Caverns State Park, Arizona, USA. Physical (color, dimensions) and chemical (elemental profile and organic carbon concentration) properties, as well as the DGGE-based bacterial community structure of the formations were analyzed. While elemental concentration was found to vary among the formations, the differences in the community structure could not be correlated with concentrations of either organic carbon or any of the elements evaluated. In contrast, the locations of formations within a distinct region of the cave as well as the relative location of specific formations within a single room were found to have a significant influence on the bacterial community structure of the formations evaluated. Interestingly, Canonical Correspondence Analysis suggests an association between the observed drip pathways (drip lines) feeding the formations (as determined by the patterns of soda straws and small stalactites that reveal water flow patterns) and the bacterial community structure of the respective formations. The results presented here indicate that a broad range of formations fed by a diversity of drip sources must be sampled to fully characterize the community composition of bacteria present on the surfaces of calcite formations in carbonate caves.     

Biogeochemical cycling of sulphur in karst and transfer into speleothem archives at Grotta di Ernesto, Italy

Trace amounts of sulphur in speleothems suggest that stalagmites may act as archives of sulphur deposition, thereby recording aspects of atmospheric variability in sulphur content. Accurate interpretation of this novel sulphur archive depends upon understanding how biogeochemical cycling in the soil and epikarst above the cave may modify the precursor atmospheric values of sulphur concentration and isotopic composition prior to incorporation into the speleothem record. Dual isotope analysis of δ³⁴S-SO₄ and δ¹⁸O-SO₄ is used to trace biogeochemical transformations of atmospheric sulphur through the cave system at Grotta di Ernesto in the Italian Alps and builds towards a framework for interpretation of speleothem sulphur archives which depends on overlying ecosystem dynamics and karst hydrological properties. A three component model of atmospheric sulphate signal modification is proposed to be driven by (1). vegetation and soil cycling, (2). the degree of groundwater mixing in the karst aquifer; and (3). redox status. The relative influence of each process is specific to individual drip flow sites and associated stalagmites, rendering each sulphur archive a unique signal of environmental conditions. Under conditions found in the soil and epikarst above Grotta di Ernesto, the dual isotope signatures of sulphate sulphur and oxygen incorporated into speleothem carbonate, closely reflect past conditions of industrial sulphur loading to the atmosphere and the extent of signal modification through biogeochemical cycling and aquifer mixing.     

The evolving landscape and climate of western Flores: an environmental context for the archaeological site of Liang Bua

The rapidly changing landscape of the eastern Indonesian archipelago has evolved at a pace dictated by its tropical climate and its geological and tectonic history. This has produced accelerated karstification, flights of alluvial terraces, and complex, multi-level cave systems. These cave systems sometimes contain a wealth of archaeological evidence, such as the almost complete skeleton of Homo floresiensis found at the site of Liang Bua in western Flores, but this information can only be understood in the context of the geomorphic history of the cave, and the more general geological, tectonic, and environmental histories of the river valley and region. Thus, a reconstruction of the landscape history of the Wae Racang valley using speleothems, geological structure, tectonic uplift, karst, cave, and terrace development, provides the necessary evidence to determine the formation, age, evolution, and influences on the site. This evidence suggests that Liang Bua was formed as two subterranean chambers ∼600 ka, but could not be occupied until ∼190 ka when the Wae Racang wandered to the southern side of the valley, exposing the chamber and depositing alluvial deposits containing artifacts. During the next ∼190 k.yr., the chambers coalesced and evolved into a multi-level and interconnected cave that was subjected to channel erosion and pooling events by the development of sinkholes. The domed morphology of the front chamber accumulated deep sediments containing well stratified archaeological and faunal remains, but ponded water in the chamber further prevented hominin use of the cave until ∼100 ka. These chambers were periodically influenced by river inundation and volcanic activity, whereas the area outside the cave was greatly influenced by glacial phases, which changed humid forest environments into grassland environments. This combined evidence has important implications for the archaeological interpretation of the site.     

猿人洞的溶洞演化和堆积旋回与北京猿人生活环境

猿人洞的溶洞演化过程按岩溶洞穴发生发展规律可划分为６个阶段．在洞穴发育的填充过程中,依据堆积物的成因类型,猿人洞中的中更新世洞穴堆积层可分为７个堆积旋回．每个堆积旋回可与年代相当的黄土堆积旋回和深海气候旋回—一对应．堆积旋回所显示的气候和洞穴环境变化均与北京猿人生活环境及其旧石器文化的发展有着密切的关系．     

兖滕两淮地区采煤塌陷地的类型与综合开发生态模式

以能源开发为主体的兖滕两淮地区是我国近期１９个国土综合开发的重点地区之一,该区采煤及其引起的土地塌陷形成的区域生态环境是一个破坏多于建设、开发多于整治的脆弱生态系统。通过实地调研,将该区采煤塌陷地分为非积水塌陷干旱地、塌陷沼泽地、季节性积水塌陷地、常年浅积水塌陷地和常年深积水塌陷地共５大类,依次相应提出了农林业综合开发与建材开发、农林渔综合开发、渔林农综合开发和水产养殖综合开发等６种不可替代的生态模式。这些模式的实施,将有力地促进兖滕两淮地区经济和社会的持续稳定发展以及生态环境的恢复良化。